CVE-2026-21513 Microsoft MSHTML Framework Protection Mechanism Failure
An attacker can bypass security features in the MSHTML Framework on Windows, potentially enabling further exploitation.
- Exploited in the wild
- Since 10 Feb 2026
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-21513?
CVE-2026-21513 is a high-severity vulnerability in Microsoft Windows 10 1607, published on 10 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.
Weakness: CWE-693
Which versions are affected by CVE-2026-21513?
It affects 13 products.
Products include Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 23h2, Microsoft Windows 11 24h2 and 7 more.
How do I fix CVE-2026-21513?
No fix has been published for CVE-2026-21513 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 3 Mar 2026.
Is CVE-2026-21513 being exploited?
Yes. Attackers have exploited CVE-2026-21513 in the wild since at least 10 Feb 2026.
Other vulnerabilities in Microsoft Windows 10 1607
- CVE-2026-33824 Microsoft Internet Key Exchange (IKE) Service Extensions Double Free
- CVE-2026-21510 Microsoft Windows Shell Protection Mechanism Failure
- CVE-2023-32049 Microsoft Windows Defender SmartScreen Security Feature Bypass
- CVE-2023-29360 Microsoft Streaming Service Untrusted Pointer Dereference
- CVE-2026-85880 Microsoft Windows Heap-Based Buffer Overflow
Sources
Also known as GHSA-rqf6-jf48-p6rm.